Lethal composition for insects



. are unstable and variable.

Patented Feb. 16, 1943 UNITED STATES A PATENT OFFICE LETHAL COMPOSITION FOR INSECTS Jared R. Ford, Washington, D. 0., and Howard W.

Eek,

East Lansing, Mlch., assignors to Kilgore Development Corporation, Washington, D. 0.,

a corporation of Virginia Application April 4, 1939,

No Drawing.

Serial No. 266,035

11 Claims.

. been onerous to manufacturers of liquid contact insecticides who rely on pyrethrum for the principal active ingredient of their product. More recently, an insecticidal spray has been prepared synthetically by diluting a suitable organic thiocyanate. This, however, introduces undesirable odors, especially at the higher concentrations now required for the so-called "high kill insecticides.

Contact sprays of pyrethrum or of organic thiocyanate are of a type to induce an initial paralytic effect in insects, but they entail a disadvantage in that at an economic concentration the paralytic eflect so produced is only temporary in a large percentage of cases. Hence, a considerable number of the insects sprayed with such an insecticide completely recover.

To avoid this dimculty and obtain the high kill demanded of a modern insecticidal spray, manufacturers have been forced to increase the concentration of these paralytic ingredients to a point where the cost of the spray produces a serious sales resistance.

Hence. an object of our invention is to provide a chemical that will be compatible with the paralytic agents named as well as being capable of supplementing their insecticidal values. Another object is to provide chemicals of such insecticidal activity that a relatively small amount will replace a substantial or major amount of the paralytic agents now required to produce a satisfactory insecticidal spray. A special object of importance is to supplement paralytic agents of insecticidal sprays by new components that are of high lethal value to insects. More parsecticide. Also, an object of our. invention is to provide a chemical insecticide synthetically from readily available raw materials and at economical cost. This will render its use economically advisable in liquid insecticides and more particularly effect a substantial savings in replacing a substantial or major part of the py rethrum or of the thiocyanate paralytic agents now required. Another object of our invention is to produce an insecticidal material that will have also satisfactory concomitant physical properties. such as freedom from odor, color, skin irritation and other untoward physiological effects on warm blooded animals. A special ob- Ject, further, is the production of certain new and useful chemical compounds.

These and other objects will appear in the illustrative description of this invention more fully to be set forth, and defined in the appended claims.

Attainment of these objects is a result of our discoveries concerning organic chemical compounds of an indandione type. These may be expressed in terms of their structural formula:

in which R is a hydrocarbon radical. We have discovered certain new chemical compounds of this formula, and also have found that all compounds of thi type exhibit high lethal power for insects. Moreover, under this invention, small amounts of these lethal compounds exhibit such synergistic effect with the above paralyzing compounds, especially pyrethrum, as to produce exceedingly useful insecticides. This invention utilizes small quantities of these indandione compounds with dilute solutions of pyrethrum extract to obtain an insecticide having the combined properties of rapid paralysis plus high killing power,

Under preferred practice of this invention appropriate quantities of these indandione compounds are distributed in a base for contacting insects. It will be illustrative to refer to pyrethrum extract dissolved in kerosene as a base, but

without limitation either to pyrethrum or to kerosene, as other paralyzing chemicals are being developed and other solvents or also emulsified bases. These are typical 01 a paralyzing insecticide and a volatile solvent well known in this art: a 2.5% solution in kerosene of a 20:1 pyrethrum extract serves as an illustrative standard. Examples will serve to describe various compositions 01' this invention. In a preferred composition under this invention the indandione compound, fl-isovaleryl-LS-indandione. is or outstanding value.

These examples are expressed in terms familiar in the art as "knockdown" and as "kill" power. They are evaluated according to present standard procedures, utilizing the so-cailed Pest-Grady method. In this a group of 100 flies is released within a gas chamber 6 x 6 x 8 ieet; then 12 cc. oi the solution .ior test is sprayed into the chamber with a De Vilbiss atomizer, Special No. 5004. At the end oi ten minutes the chamber is ventilated and the flies that have been knocked down are transferred to an observation cage and supplied with food. At the end of twenty-four hours the numbers of dead and living flies are determined. The number 01 flies on the floor o! the chamber in 10 minutes will hereinafter be designated as the "knockdown and the number dead at the end of 24 hours as the kill."

It is well known that the resistance oi house flies to insecticides varies widely. In order to compensate for this variation, concurrent checks on the resistance of the flies to standard pyrethrum insecticide were run on a group 100 flies from the same case as those used in testing the unknown sample. The order of the test was such that every unknown sample had a control group of 100 flies tested immediately before or immediately after it. The standard pyrethrum insecticide used as a control was the ci'iicial test insecticide o! the National Association of Insecticide and Disinfectant Manufacturers. This oflicial test insecticide represents the average product that is obtained by diluting one part of 20: 1 pyrethrum concentrate with nineteen parts of a deodorised kerosene having a boiling range 01' approximately 345 to 510' I".

The results obtained from a pair of tests, that is. one test on the unknown sample and one test on the oilicial test insecticide, were then adlusted statistically to the basis of a 50% kill for y the ofiiciai test insecticide by the method published by one 01' us in Soap magazine. June. 1937, page 116. Thus, if a pair 01' tests that were run on two groups of 100 flies taken from the same cage gave a 60% kill for the O. T. I. and 90% kill for the sample, the adjusted hll tor the sample on the basis of a 50% kill iorthe O. T. I. would be 85%. In the following tables all the figures for per cent kill are so adjusted.

EXAMPLEI wherein R is a hydrocarbon radical.

1 10 min Test M 24 hr.

etcrial and concentration knock- No. do kiii Per cent Per cent 1 2.5 20:1 pyrethrum concentrate 00.9 25 2 2.6 20:1 pyrethrum concentrate-|-0.5 100 4a Y 11.7100 cc. 2-Acetyi-i,8-indandione. .3 2.59 93:1 pyrcthrum conccntrate+0.6 100 Bil 3.7100 cc. Z-propionyi-i,s-indandione.

4 2.57 2):] pyrethrum concentnte+0.5 100 73 gjlun cc. 2-butyryi-L3indandione. 5 2.67 20:1 pyrethrum concentrate+0Ji 97. 5 M

g. 00 cc. 2-isobutyryl-i,3-indanone. 6 2.57 21:1 pyrethruin concentrate-+1.0 100 98 7100 cc. Msovaieryi-l,a-indandione. 7 2.67 2M1 pyrethrum concentrate-+0.5 I00 89 1.7100 cc. z-isovaleryl-hs-indandione 8 2.67 51:1 pyrethrum concentrate-+0.25 100 U 67 5.7100 cc. Z-iQovaieryi-l .(i-indandione. 9 2.59? 20:1 pyrethmm concentrate-His 99. 6 76 g. 100 cc. 2-valoryl-i,&indandione. 10 2.57 20:] pyrethrum concentrate-+0.5 100 .100 cc. 2-trimethylacetyl-L3inendione. ii 2.57 1):] pyrethrum concentrate+0.5 63

1;.7100 cc. 2-caproyl-l,3-indandione. 12 2.57 20:1 pyrethrum concentrate+0.ii 100 1 @7100 cc. 2-hexahydrobenroyi-l,3-

ndandione. 13 2.57 20:1 pyrethrum concentrated-0.6 99.0 42

.7100 cc. 2 (2-phenylethyi)-l,3- ndandione. 14 2.5% Zlzl pyrethrum ooncontratc+0.t 100 55 12.1100 cc. z-benzoyl-La-indandiona it 2.5% 20:! p thrum concentrate+l% 99.9 83

residue 0 taiued from the cialsen condensation between dimethyl hthaiate and moth l isobut 1 stone as described in xample I iii 2.03.1100 cc.2-isovaleryi-i,8-indandione 96 96 The above examples show the use 01' these compounds with pyrethrum. except that examples 1 and 16 are respectively for pyrethrum alone and the indandicne compound alone. The compounds when used alone are eiiective killing agents but are somewhat delayed in their action. In the last example, it is to be noted that although the knockdown was inferior to the samples containing pyrethrum, the material killed practically all oi the flies that it knocked down, while in the first example the 2.5% of 20: 1 pyrethrum concentrate gave a complete knockdown but 75% of the flies recovered. The compounds are more useful when incorporated with a material such as pyrethrum which paraiyzes the flies rapidly.

In these insecticides, lethal effect is imparted generally by indandione compounds of the formula- 0 CH-E-R wherein R is a butyl group generally; that is, normal butyl, isobutyl, secondary butyl or tertiary butyl.

The combination of these compounds with pyrethrum produces a synergistic client. that is to say, more than the additive efiect oi the two ingredients. This efl'ect may be demonstrated by using a paralyzing agent other than the type oi pyrethrum to obtain the rapid knockdown. Thus, in table II, we have shown the results oi kill tests run on comparatively weak solutions of pyrethrum extract and "ii-ethane 884" (a solution of approximately 50% p-butoxy-p'-tliiocyanodiethyl ether in kerosene). Pyrethrum or Lethane 384" when used by themselves give approximately the same kill. However, when an was produced.

TAIL! II Syneroistic efiect when used with pyrethmm Material and concentration Kill 2 W th trate yre rum concen 2% fiethane 384" 20:1 pyrethrum conoentrate+0.5 g.1i ec. 2-lso vgioryi-LB-indandione 2%iLLethane 384"+0.5 g.1l00 cc. H-IsoVaIeryi-LB-Indsn- 0 no. 2.57 20:1 pyrethrum concentrate-+0.5 g.1l00 cc. 2 hutyryl- 1,-indandione 27 "bethane 384"+.5 3.1100 cc. i-butyryl-LB lndaudiona- 2.; 20:1 pyrethrum concentrate+0.5 g.1l00 cc. B-hexb hydrobenzoyl-L3-lndandione 2% iiethane 384"+2-hershydr ,l-Llidndandione.

Compounds of the typeare suitably prepared by Claisen condensation between an ester oi phthalic acid and a methyl ketone, using the usual condensing agents for this Claisen condensation such as metallic sodium or potassium or their corresponding alcoholates.

whereinltisahydrocarbonradicalandk'isan alkyl radical.

I'or example. we have prepared the compound 2-isovaleryl-L8-indandione (where R is the isovaleryl radical) by the following method:

men

A mixture 01' 194 Parts (all parts given by weight) dimethyl phthalate and 100 parts methyl isobutyl ketone is diluted with 400 parts of dry benzene and 23 parts 01' metallic sodium is added in small pieces. When the sodium has dissolved, the reaction mixture is extracted with water and the aqueous extracts acidified. A yellow brown oil separates and crystallizes upon standing. Upon recrystallization from methanol, a light yellow solid, melting at 67, is obtained. The carbon-hydrogen analysis and neutral equivalent indicate that this compound is 2-isovaleryl-1,3-indandione.

Carbon-hydrogen cochlea-Calculated for CMHHOI: carbon 73.00%, hydrogen 6.24%. Found: carbon 73.01%, hydrogen 8.13%.

Molecular weicht (Roux-Calculated 230. Found 207.

Neutral equivalent calculated.-230. Found 225, 229.

The structural formula 01' 2-Isovaleryl-l.3-

indandione is:

The other members of the series of compounds under this invention may be prepared in similar manner. In some cases, where the final compounds themselves were not crystalline. they were purified by recrystallizing their salts (for example, sodium salts) and then acidifying.

The following table lists illustrative compounds of the series- An illustrative example is: 1-" 0 0 G008 a o OH; -R Na cH (|-|3 R coon' 0-Ne F. J! o 56 4 described as insecticidals in Example I, the ke- 0- tones from which they were prepared and the melting point 01' the iinal products. These sub- 6 stantiate the broad designation oi R by the term i 00 hydrocarbon.

Tau: III

R of the t M It! iormula 00mm Kama pain? mtyi-LHndsndione Acetone 109mm". 2- pionyl-l,ii-indandione... Methyl ethyl ketone 101. 2- utyryl-1,$-Indandione.. Methyl opyiketone1..... Oil. 2-lsobu l-iJ-lndandionel Methyl progylketone....

2-vale 1,841: dione Methyl butyl etone Oil. fl-isov yi-l,3-indandlone Methyl isobutyl ketonelun 67. z-trimethylacotgl-hii-indandlone. Plnaoolone h 1091m. Do i. Il'C|Hn... 2-caproyi-Lbin audlone MethyLn-amylketone Ii7-38. cyeioalkyi Cycle-Cami. 2-hexahydrobensoyi-l a-indaudluna. Methyl cycloheryi ketoue 7980. kyL... CiHIOHICHL %(2-phe?lethyl -l,ii-i'ndaudione.... i-phenim-butanone 77. i (Jim 2-bensoy 1,8- ione .l Acetop cnone l03-l0fi.

! Technical methyl lketone used. This was a mixture oi about meth i n-pro yi ketone and 20 1 MP7 I P This invention is not restricted to the use of pure forms of compounds of the type- The crude product obtained from the Claisen condensation of a dialkyl phthalate with a methyl ketone may be incorporated directly in an insecticide without isolating and purifying the pure compound. The following example will show how this may be done:

EXAMPLEIII A mixture of 194 parts (all parts given by weight) oi diamethyl phthalate and 100 parts methyl isobutyl ketone is diluted with 400 parts of dry benzene, and 23 parts of metallic sodium are added in small pieces. When the sodium has dissolved, the reaction mixture is agitated thoroughly with a slight excess of dilute acid. The benmne layer is separated, washed with water and the wet benzene removed under reduced pressure. One part of the resulting brown, sticky residue was shaken with 99 parts 01' petroleum distillate containing 2%% 20:1 pyrethrum concentrate. A small amount oi insoluble material was filtered out and the resulting solution bioassayed by the Feet-Grady method. The resulting insecticide gave a 63% kill.

Furthermore, we have found that the compounds of the typewherein R. is a hydrocarbon radical are quite stable towards sunlight. It is well known that extracts of botanical insecticides such as pyrethrum, derris, cube and the like, are very unstable in the presence of sunlight and their efl'ectiveness as insecticides is rapidly destroyed. The following example demonstrates the stability of our compounds:

EXAMPLEIV Two hundred cubic centimeters of deodorized kerosene containing 2.0 grams of 2-isovaleryl-i,3- indandione were placed in a bottle made of Corex glass. as special glass which transmits a large percentage of the shorter wave lengths of light which have been found to be especially destructive to pyrethrum and rotenone. The bottle was placed outdoors on the south side of the building where it received the direct sunlight whenever the weather was clear. The bottle was allowed to remain outside from February 18 to March 20. At the end of this time 2/,;% of 20:1 pyrethrum concentrate was added. If no decomposition had occurred, the material would have given the same kill that it did before being exposed to the sunlight, namely, 98% (see Example 1, test No. 8). Actually, it was found to give a 94% kill.

Thus, it is evident that these new insecticidals are useful not only for household use, but also out of doors in the sunlight, and for use on plants or trees where rotenone is unsatisfactory.

In the foregoing description this invention has been illustrated by compositions in which petroleum distillates serve as distributing means or diluent for these new insecticidal materials. However. this invention is applicable also to use of other distributing means such as aqueous emulsions or organic emulsions, or also powders that may serve as distributing agents.

While this invention has been described by illustrative, preferred examples in accordance with the patent statutes. it will now be apparent to those skilled in this art that the principles of this invention may be embodied in other forms than those specifically set forth, but within the scope of the appended claims.

What we claim is:

1. An insecticide comprising a compound of the type ca-i i-a C II 0 wherein R is a hydrocarbon radical. the compound servlng to impart lethal qualities to the insecticide.

2. An insecticide comprising a compound of the type wherein R is a hydrocarbon radical, and pyrethrum, the compound serving to impart lethal qualities to the insecticide.

3. An insecticide comprising a product obtained by Claisen condensation between a dialkyl phthalate and a methyl ketone, the product serving to impart lethal qualities to the insecticide.

4. An insecticide comprising pyrethrum and a product obtained by a Claisen condensation between a diailwl phthalate and a methyl ketone. the product serving to impart lethal qualities to the insecticide.

5. An insecticide comprising pyrethrum and a product obtained by a Claisen condensation between a dialkyl phthalate and a methyl isobutyl ketone, the product serving to impart lethal qualities to the insecticide.

6. An insecticide comprising an insect-paralyzing agent intermixed with a compound of the type- CH-C-R C II 0 wherein R is a hydrocarbon radical, the compound serving to impart lethal qualities to the insecticide.

7. An insecticide comprising an insect-paraiyzing agent and a compound of the type- CH-ER 1',

where-in R is the isovaieryl group, the compound serving to impart lethal qualities to the insecticide.

9. An insecticide comprising pyrethrum and 2- iscvsleryi-LS-indandione. the indandione compound serving to impart lethal qualities to the insecticide.

10. An insecticide comprising an insect-para.- lyzlng agent and 2-vsleryl-1,3-indandione, the indandione compound serving to impart lethal quality to the insecticide.

11. An insecticide comprising an insect-paralyzing agent and 2-caproyl-L3-indandione, the indandione compound serving to impart lethal quality to the insecticide.

JARED H. FORD. HOWARD W. ECK. 

